In a general sense, the invention is directed to systems and methods for treating interior tissue regions of the body. More specifically, the invention is directed to systems and methods for treating dysfunction in body sphincters and adjoining tissue, e.g., in and around the lower esophageal sphincter and cardia of the stomach.
The gastrointestinal tract, also called the alimentary canal, is a long tube through which food is taken into the body and digested. The alimentary canal begins at the mouth, and includes the pharynx, esophagus, stomach, small and large intestines, and rectum. In human beings, this passage is about 30 feet (9 meters) long.
Small, ring-like muscles, called sphincters, surround portions of the alimentary canal. In a healthy person, these muscles contract or tighten in a coordinated fashion during eating and the ensuing digestive process, to temporarily close off one region of the alimentary canal from an other.
For example, a muscular ring called the lower esophageal sphincter surrounds the opening between the esophagus and the stomach. The lower esophageal sphincter (or LES) is a ring of increased thickness in the circular, smooth-muscle layer of the esophagus. Normally, the lower esophageal sphincter maintains a high-pressure zone between fifteen and thirty mm Hg above intragastric pressures inside the stomach.
When a person swallows food, muscles of the pharynx push the food into the esophagus. The muscles in the esophagus walls respond with a wavelike contraction called peristalsis. The lower esophageal sphincter relaxes before the esophagus contracts, and allows food to pass through to the stomach. After food passes into the stomach, the lower esophageal sphincter constricts to prevent the contents from regurgitating into the esophagus.
The stomach muscles churn the food and digestive juices into a mass called chyme. Then the muscles squeeze the chyme toward the pyloric (intestinal) end of the stomach by peristaltic waves, which start at the top of the stomach and move downward. The pyloric sphincter, another ringlike muscle, surrounds the duodenal opening. The pyloric sphincter keeps food in the stomach until it is a liquid. The pyloric sphincter then relaxes and lets some chyme pass into the duodenum.
Dysfunction of a sphincter in the body can lead to internal damage or disease, discomfort, or otherwise adversely affect the quality of life. For example, if the lower esophageal sphincter fails to function properly, stomach acid may rise back into the esophagus. Unlike the stomach, the esophagus has no natural protection against stomach acids. When the stomach contents make contact with the esophagus, heartburn or other disease symptoms, including damage to the esophagus, can occur.
Gastrointestinal reflux disease (GERD) is a common disorder, characterized by spontaneous relaxation of the lower esophageal sphincter. It has been estimated that approximately two percent of the adult population suffers from GERD. The incidence of GERD increases markedly after the age of 40, and it is not uncommon for patients experiencing symptoms to wait years before seeking medical treatment.
GERD is both a normal physiologic phenomenon that occurs in the general population and a pathophysiologic phenomenon that can result in mild to severe symptoms.
GERD is believed to be caused by a combination of conditions that increase the presence of acid reflux in the esophagus. These conditions include transient LES relaxation, decreased LES resting tone, impaired esophageal clearance, delayed gastric emptying, decreased salivation, and impaired tissue resistance. Since the resting tone of the lower esophageal sphincter is maintained by both myogenic (muscular) and neurogenic (nerve) mechanisms, some believe that aberrant electrical signals in the lower esophageal sphincter or surrounding region of the stomach (called the cardia) can cause the sphincter to spontaneously relax.
Lifestyle factors can also cause increased risk of reflux. Smoking, large meals, fatty foods, caffeine, pregnancy, obesity, body position, drugs, hormones, and paraplegia may all exacerbate GERD. Also, hiatal hernia frequently accompanies severe GERD. The hernia may increase transient LES relaxation and delay acid clearance due to impaired esophageal emptying. Thus, hiatal hernias may contribute to prolonged acid exposure time following reflux, resulting in GERD symptoms and esophageal damage.
The excessive reflux experienced by patients with GERD overwhelms their intrinsic mucosal defense mechanisms, resulting in many symptoms. The most common symptom of GERD is heartburn. Besides the discomfort of heartburn, reflux results in symptoms of esophageal inflammation, such as odynophagia (pain on swallowing) and dysphagia (difficult swallowing). The acid reflux may also cause pulmonary symptoms such as coughing, wheezing, asthma, aspiration pneumonia, and interstitial fibrosis; oral symptoms such as tooth enamel decay, gingivitis, halitosis, and waterbrash; throat symptoms such as a soreness, laryngitis, hoarseness, and a globus sensation; and earache.
Complications of GERD include esophageal erosion, esophageal ulcer, and esophageal stricture; replacement of normal esophageal epithelium with abnormal (Barrett""s) epithelium; and pulmonary aspiration.
Treatment of GERD includes drug therapy to reduce or block stomach acid secretions. Still, daily drug therapy does not eliminate the root cause of the dysfunction.
Invasive abdominal surgical intervention has also been tried with success. One procedure, called Nissen fundoplication, entails invasive, open abdominal surgery. The surgeon wraps the gastric fundis about the lower esophagus, to, in effect, create a new xe2x80x9cvalve.xe2x80x9d Less invasive laparoscopic tehniques have also been tried to emulate Nissen fundoplication, also with success. Still, all surgical intervention entails making an incision into the abdomen and carry with it the usual risks of abdominal surgery.
One aspect of the invention provides an improved interface for association with an electrode structure which, in use, is deployed in contact with a tissue region, e.g., at or near a sphincter. The interface comprises an input adapted to be attached to a sensor carried at a known location on the electrode structure to monitor an operating condition e.g., tissue temperature, or impedance, or both. The device also includes a display screen, and an operating system to generate a viewable image on the display screen. The viewable image comprises an idealized image of the electrode structure and an indicator image to represent the monitored operating condition in a spatial position on the idealized image corresponding to the location of the sensor on the electrode structure.
The indicator image can display, e.g., a value to represent the monitored operating condition, or a color to represent the monitored operating condition, or both.
In one embodiment, the input is adapted to be attached to a second sensor, carried at a second known location on the electrode structure, to monitor an operating condition. The second know location is different than the known location of the first-defined sensor. In this embodiment, the viewable image includes a second indicator image, to represent the operating condition monitored by the second sensor in a spatial position on the idealized image corresponding to the second location of the second sensor on the electrode structure.
In one embodiment, the interface further includes an output to process the monitored operating condition as data for storage or manipulation, e.g. for downloading to a storage media, or to a printer, or both.
According to another aspect of the invention, the electrode structure associated with the interface includes an electrode having a distal end that penetrates tissue in the tissue region. In this arrangement, the input is adapted to be attached to a first temperature sensor carried by the electrode structure to monitor surface tissue temperature and a second temperature sensor carried by the distal end of the electrode to monitor subsurface tissue temperature. In this arrangement, the viewable image comprises an idealized image of the distal end of the electrode in spatial relation to an idealized image of the support structure. The viewable image further includes a first indicator image representing the surface tissue temperature shown in spatial association with the idealized image of the support structure and a second indicator image representing the subsurface tissue temperature shown in spatial association with the idealized image of the distal end of the electrode.
Another aspect of the invention provides an interface for association with an electrode structure which, in use, is deployed in contact with a tissue region, e.g., at or near a sphincter. The device comprises an input adapted to be attached to a sensor deployed in association with the electrode structure to monitor an operating condition in the tissue region. The device also includes a display screen and an operating system to generate a viewable image on the display screen comprising a first indicator image to represent a current operating condition monitored by the sensor and a second indicator image to represent changes in the monitored operating condition over time.
In one embodiment, the second indicator image comprises a graph having a time axis. In one embodiment, the viewable image includes an indicator of an error condition displayed in the graph in relation to the time axis.
In one embodiment, the second indicator image includes a reference indicator representing a targeted operating condition. In this arrangement, changes in the monitored operating condition over time are displayed in relation to the reference indicator.
Another aspect of the invention provides an interface for association with an electrode structure which, in use, is deployed in contact with a tissue region, e.g., at or near a sphincter, and one or more auxiliary elements, e.g., a generator to generate energy capable of heating tissue, or a pumping mechanism to dispense cooling fluid to the tissue region, or both. According to this aspect of the invention, the interface comprises a display screen, and an operating system to generate a viewable image on the display screen. The viewable image comprises an animated visual image indicating operation of at least one of the auxiliary elements.
Another aspect of the invention provides an interface for association with an electrode structure which, in use, is deployed in contact with a tissue region, e.g., at or near a sphincter. According to this aspect of the invention, the interface comprises an input adapted to be attached to a sensor carried at a known location on the electrode structure to monitor an operating condition. The interface also includes a display screen and an operating system to generate a viewable image on the display screen. The viewable image comprises an idealized image of the electrode structure and an indicator image to represent the monitored operating condition in a spatial position on the idealized image corresponding to the location of the sensor on the electrode structure. In a first operational mode of the electrode structure, the indicator image comprises a numeric value to represent the monitored operating condition. In a second operational mode of the electrode structure, the indicator image comprise a colored shape, free of a numeric value, to represent the monitored operating condition.
Another aspect of the invention provides a method for treating a tissue region. The method deploys an electrode structure in contact with the tissue region. The electrode structure carries a sensor at a known location on the electrode structure to monitor an operating condition. The method generates an idealized image of the electrode structure and an indicator image to represent the monitored operating condition in a spatial position on the idealized image corresponding to the location of the sensor on the electrode structure. The method displays a view image comprising the idealized image and indicator image. The method causes the electrode structure to apply energy to heat the tissue region while the view image is displayed on the display screen.
Features and advantages of the inventions are set forth in the following Description and Drawings, as well as in the appended Claims.